Quinone-methide, phenolic and related triterpenoids of plants of Celastraceae: further evidence for the structure ofCelastranhydride

Quinone-methide and phenolic triterpenoids of the root outer bark ofCelastrus paniculatus have been identified as celastrol, pristimerin, zeylasterone and zeylasteral whereas those ofKokoona reflexa root outer bark were pristimerin, zeylasterone and zeylasteral. Celastranhydride, an unusual triterpene anhydride isolated fromK. zeylanica was shown to be present inK. reflexa, Cassine balae andReissantia indica. Details of the isolation and structure elucidation of celastranhydride are presented along with the analysis of¹H-detected heteronuclear multiple-bond multi-quantum correlation (HMBC) NMR spectrum which aided the confirmation of its structure. Extracts ofC. balae, Gymnosporia emarginata, Pleurostylia opposita andR. indica were found to contain quinone-methides but were devoid of phenolic triterpenoids. The biosynthetic and chemotaxonomic significance of the co-occurrence of these triterpenoids in Celastraceae is discussed.